Elon Musk described autonomous-driving technology as “transformative” to Tesla Inc. (TSLA.O) in a call aimed at ginning up interest in the electric-car maker’s US$2 billion debt and stock offering, according to two people who dialed in.

The chief executive officer said autonomy is a fundamental driver for Tesla and key to how it could become a “half-trillion dollar market cap company,” said the people, who asked not to be identified because the call wasn’t open to the public. A Tesla spokesman didn’t immediately respond to a request for comment.

The comments build on the case that Musk made during an investor day focused on autonomy last week that Tesla is on the cusp of having 1 million vehicles on the road that will be fully capable of driving themselves. The billionaire plans to put those cars into a shared robotaxi service that the CEO described as being lucrative for both the company and its customers.

Ahead of the call, Tesla filed to raise at least US$2 billion through debt and stock offerings, after a dismal first quarter depleted its cash balance to the lowest level in three years. Goldman Sachs and Citigroup hosted the call for investors at 11 a.m. New York time with Musk and Zachary Kirkhorn, Tesla’s chief financial officer, the people said.

Tesla delivered just 63,000 cars in the first quarter but said in a letter to shareholders last week that it expects to deliver between 90,000 and 100,00 vehicles in the second quarter. Kirkhorn re-affirmed that forecast during the Thursday call, the people said.

Tesla shares climbed 4.3 per cent, their biggest jump since Feb. 27, to close at US$244.10. The stock has dropped 27 per cent this year.